Effects of lithium salts on pain experience in depressed patients.

15 depressed female patients were studied for sensitivity to pain stimuli before and after 1 month of treatment with lithium salts. By electric stimulation techniques, an aspecific sensitivity threshold, a pain sensitivity threshold and a pain tolerance threshold were measured and their relationship were evaluated. In this investigation, we evaluated the influence of the improvement of the clinical picture and of the blood levels of the drug on pain perception. Our data seem to suggest an analgesic action of lithium, which, however, appears to be partially masked by the effects on pain perception induced by the evolution of the depressive picture.